The multinational study in almost 1,200 subjects incorporates input from leading medical experts from Europe and North America, and follows a constructive End of Phase 2 meeting with the US Food and Drug Administration, Scientific Advice from the European Medicines Agency and regulatory guidance from Health Canada, informing the path to registration in each territory.

The ToleroMune® cat allergy treatment phase 3 study follows positive results from a number of phase 2 trials. On September 17, the prestigious Journal of Allergy and Clinical Immunology published phase 2 data showing patients had a significantly greater reduction in symptoms compared with placebo one year after the start of the study, despite receiving only a four-dose course of treatment over 12 weeks*.

"Allergy to cat dander is a common condition, and can greatly reduce patients' quality of life, impact work or school performance and exacerbate asthma symptoms," said the study's Principal Investigator, Professor Harold S Nelson MD of National Jewish Health, Denver, Colorado. "ToleroMune® cat allergy treatment represents a different therapeutic approach to existing therapies, with phase 2 data suggesting it is the most exciting innovation in the field of allergy for decades. Maintaining sustained allergen tolerance over an extended period without requiring ongoing dosing would represent a major step forward, and this large ToleroMune® cat allergy treatment phase 3 study aims to confirm definitively if this can be achieved."

"Circassia's goal is to revolutionise the treatment of allergy, and the start of this phase 3 study with our lead productis a major strategic milestone in this endeavour," said Steve Harris, Circassia's CEO. "Tens of millions of people are allergic to cats in the United States and Europe, and the disease can have a major effect on patients' quality of life. For many years sufferers have had limited treatment options, and currently no short, simple treatment with long-lasting impact on the disease is available. We believe our ToleroMune® technology has the potential to address this unmet medical need, and our initiation of the final phase of clinical development demonstrates our commitment to helping improve patients' lives."

Trial design

The randomised, double-blind, placebo-controlled, multi-centre, international field study plans to enrol 1,182 patients aged 12 - 65 years old with cat allergen-induced rhinoconjunctivitis. The trial will include approximately 110 centres located in the United States, Canada and five countries in Europe. The study will evaluate the safety and efficacy of both a single course and two courses of investigational ToleroMune® cat allergy treatment, with each course consisting of four standardised doses administered over 12 weeks. The trial's primary efficacy endpoint will be the combined reduction in rhinoconjunctivitis symptoms and rescue medication use one year after the start of treatment, compared with placebo. The study is expected to complete in Summer 2014.

About cat allergy

Allergies are a significant global health issue. Allergic rhinoconjunctivitis (ARC) affects up to 30% of adults and 40% of children in developed countries, and its prevalence is rising. ARC reduces quality of life and impacts school and work attendance and performance. In Continental Europe and the USA, cat allergy is one of the most common forms of the disease, and affects 10 - 15% of those with ARC and / or asthma. As cat dander is widespread in the human environment, and widely found in public buildings, patients with cat allergy may experience significant symptoms despite attempting to avoid exposure. Current treatment options include temporary symptom suppression with antihistamines, corticosteroids and cromones, or long-term whole allergen immunotherapy, which can take three - five years and has the potential to induce life-threatening anaphylactic reactions.

About ToleroMune®

Circassia's investigational cat allergy treatment is based on the company's novel, proprietary ToleroMune® technology. This uses rationally-designed combinations of synthetic allergen-derived peptides to generate regulatory T cells to suppress allergic responses and induce immune tolerance. Circassia's lead ToleroMune candidate consists of seven peptides derived from the major cat allergen Fel d 1. It has successfully completed a number of phase 2 studies, which demonstrated that courses of short, simple treatment can reduce patients' symptoms and have a favourable safety profile. In a longer-term phase 2 follow-up study*, patients' rhinoconjunctivitis symptoms were improved significantly one year after the start of dosing compared with placebo, despite no further treatment after the initial four doses given over 12 weeks (49.5% improvement in total symptom score vs 20.4% on placebo; p=0.01). This level of improvement is substantially higher than that achieved in similar studies by a number of other treatment approaches used in allergy.

About Circassia

Circassia was founded by a team of highly experienced biotechnology scientists and entrepreneurs, and is chaired by the former Chairman of GlaxoSmithKline, Sir Richard Sykes. The company is based in the UK on the Oxford Science Park, and its joint venture with McMaster University (Adiga Life Sciences Inc) is located in Hamilton, Canada. Circassia's ToleroMune® technology was developed originally by scientists at Imperial College, London. Having successfully completed five fundraising rounds, Circassia has raised approximately £105 million ($178 million) and is backed by a syndicate of world-class institutional investors, including Imperial Innovations and Invesco Perpetual.